The instant invention provides a polyethylene blend-composition suitable for blown films, and films made therefrom. The polyethylene blend-composition suitable for blown films according to the present invention comprises the melt blending product of: (a) from 0.5 to 4 percent by weight of a low density polyethylene having a density in the range of from 0.915 to 0.935 g/cm.sup.3, and a melt index (I.sub.2) in the range of from greater than 0.8 to less than or equal to 5 g/10 minutes, and a molecular weight distribution (M.sub.w/M.sub.n) in the range of from 6 to 10; (b) 90 percent or greater by weight of a linear low density polyethylene composition has a density in the range of 0.900 to 0.935 g/cm.sup.3, a molecular weight distribution (M.sub.w/M.sub.n) in the range of 1.5 to 4.5, a melt index (I.sub.2) in the range of 0.1 to 5 g/10 minutes, a molecular weight distribution (M.sub.z/M.sub.w) in the range of less than 3, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of said composition, and a zero shear viscosity ratio (ZSVR) in the range from 1 to less than 2; (c) optionally a hydrotalcite based neutralizing agent; (d) optionally one or more nucleating agents; (e) and optionally one or more antioxidants.

The present invention relates to a multimodal polyethylene composition which can be manufactured into pipes showing improved pressure resistance comprising a high density multimodal ethylene polymer component (A) having a density of at least 930 kg/m.sup.3, and a MFR.sub.21 of not more than 15 g/10 min, wherein said composition exhibits a LAOS-NLF defined as $LAOS-NLF=.Math.\frac{G_1^{}}{G_3^{}}.Math.$ where G.sub.1first order Fourier Coefficient G.sub.3third order Fourier Coefficient
of at least 1.7. Such a polyethylene composition is useful for the manufacture of pressure pipes that exhibit improved pressure resistance and creep resistance and do not undergo sagging. Further disclosed is a process for the production of a pipe using such a multimodal polyethylene composition and a pipe comprising such a multimodal polyethylene composition.

Provided herein are polymerization processes and polymer compositions including reactor blends formed by such polymerization processes. The polymerization processes include copolymerization using two metallocene catalyst systems: the first catalyst system capable of producing polymers having 60% or more vinyl terminations, the second catalyst system capable of producing high molecular weight polymers, preferably incorporating at least some of the polymers produced by the first catalyst system into the high molecular weight polymers. The reactor blends formed thereby therefore include first and second copolymer components, which may differ in monomer content and weight-average molecular weight (Mw). Furthermore, the reactor blends may exhibit advantageous rheological properties, at least some of which are consistent with long-chain branching. Preferred reactor blends comprise ethylene-propylene-diene (EPDM) terpolymers.

An impact modifier composition (IMC) is disclosed comprising (a) a polyolefin plastomer (POP), and (b) at least one block copolymer. The POP has a density of 0.870 to 0.920 g/cm.sup.3, a MFI of 0.5 to 30 g/10 minutes at 190 C./2.16 kg, a melt index ratio of 10 to 22, and a long chain branching (LCB) of <15 LCB/10.sup.6 carbons. The at least one block copolymer is selected from (i) a first hydrogenated styrenic block copolymer (first HSBC), (ii) a second hydrogenated styrenic block copolymer (second HSBC), and (iii) at least one multi-arm block copolymer (MABC). Each first HSBC and second HSBC has a polystyrene content (PSC) of 3 to 20 wt. %, and 15 to 30 wt. %, respectively. The impact modifier composition can be used in polyolefin compositions to improve impact resistance and a balance of other mechanical properties.

The present disclosure relates to a polyethylene composition with improved swell ratio and mechanical properties for use in preparing blow-molded articles and having the following features: 1) a density from 0.945 to less than 0.952 g/cm.sup.3; 2) an MIF/MIP ratio from 15 to 30; 3) a Shear-Induced Crystallization Index (SIC) from 2.5 to 5.5.

Embodiments of the present disclosure relate to a method of preparing polyethylene compositions comprising polymerizing ethylene in a first gas-phase reactor and polymerizing ethylene in a second gas-phase reactor in the presence of hydrogen; wherein at least one of the first or second gas-phase reactors comprises a first and second polymerization zone; wherein a hydrogen pressure of the first and second polymerization zones are different such that at least a portion of the second ethylene cycles through the first and second polymerization zones and a gas mixture of each polymerization zone is partially or totally prevented from entering the other zone.

The present invention relates to a multimodal polyethylene composition which can be manufactured into pipes showing improved pressure resistance comprising a high density multimodal ethylene polymer component (A) having a density of at least 930 kg/m.sup.3, and a MFR.sub.21 of not more than 15 g/10 min, wherein said composition exhibits a LAOS-NLF defined as

[00001]$L.Math..Math.A.Math..Math.O.Math..Math.S-N.Math..Math.L.Math..Math.F=.Math.\frac{G_1^{}}{G_3^{}}.Math.$ where G.sub.1first order Fourier Coefficient G.sub.3third order Fourier Coefficient
of at least 1.7. Such a polyethylene composition is useful for the manufacture of pressure pipes that exhibit improved pressure resistance and creep resistance and do not undergo sagging. Further disclosed is a process for the production of a pipe using such a multimodal polyethylene composition and a pipe comprising such a multimodal polyethylene composition.

Ethylene-based polymers having a density of 0.952 to 0.965 g/cm.sup.3, a high load melt index (HLMI) from 5 to 25 g/10 min, a weight-average molecular weight from 275,000 to 450,000 g/mol, a number-average molecular weight from 15,000 to 40,000 g/mol, a viscosity at HLMI from 1400 to 4000 Pa-sec, and a tangent delta at 0.1 sec.sup.?1 from 0.65 to 0.98 degrees. These polymers have the processability of chromium-based resins, but with improved stress crack resistance, and can be used in large-part blow molding applications.

The present invention is directed to a modified polypropylene comprising from 0.3 to 2 long-chain branches per 1,000 carbon atoms, wherein said long-chain branch has more than 1,000 carbon atoms and 0 to 6% of ethene and/or alpha-olefinic comonomer having 3 to 18 carbon atoms. The polypropylene of the present invention is a homopolymer, a random copolymer, or a heterophasic copolymer. The present invention also relates to large, deep, complex and/or thick articles which are thermoformed from said polypropylene. Furthermore, the present invention relates to the process for thermoforming said modified polypropylene into large, deep, complex and/or thick articles. The present invention also relates to the use of the polypropylene to prepare large, deep, complex and/or thick articles.

The present disclosure relates to a polyethylene composition with improved swell ratio and mechanical properties for use in preparing blow-moulded articles and having the following features: 1) a density from 0.945 to less than 0.952 g/cm.sup.3; 2) an MIF/MIP ratio from 15 to 30; 3) a Shear-Induced Crystallization Index (SIC) from 2.5 to 5.5.